1. Field of the Invention
The present invention relates to a vertical heat-treating apparatus constituted by a plurality of substantially vertical reactor bodies aligned with each other.
2. Description of the Related Art
As a conventional heat-treating apparatus for heating a substrate to be treated, such as a semiconductor wafer, to form a thin film or to perform thermal diffusion, a horizontal heat-treating apparatus constituted by a horizontally arranged reaction tube has been mainly used. However, in recent years, a vertical heat-treating apparatus constituted by a substantially vertically arranged reaction tube has been put into use.
That is, in the vertical heat-treating apparatus, a reactor body comprising a cylindrical reaction tube made of quartz or the like, a heater provided to surround the reaction tube, a holding tube, a heat insulator, or the like is almost vertically arranged. A large number of semiconductor wafers are stacked at intervals on a wafer boat made of quartz or the like, and the semiconductor wafers are loaded/unloaded in the reaction tube by, e.g., a conveying mechanism which can be vertically moved.
In this apparatus, various gases or the like must be supplied to the reactor body to treat an object stored in the reactor. Therefore, other various units 24 (to be also referred to as a gas feed unit of a source gas and the like) are arranged, for example, as shown in FIG. 1 with respect to an installation area 25 of a reactor body 21.
In this case, a maintenance operation for the reactor body 21 is performed in directions of, e.g., arrows "a", and a maintenance operation for the other various units is performed from almost four sides of a frame (housing) in directions of arrows "b".
In the vertical heat-treating apparatus, since a wafer boat can be loaded/unloaded without contacting the inner wall of the reaction tube, almost no particles are generated, an occupied area is small, and the diameter of the semiconductor wafer to be treated can be easily increased.
However, in the conventional vertical heat-treating apparatus, when a maintenance area along the four sides of the apparatus is required and the vertical heat-treating apparatuses are sequentially aligned with each other, the maintenance space between the apparatuses is increased, and the installation floor space is inefficiently used. In order to align all the apparatuses as a system, a semiconductor wafer to be treated must be conveyed for a long distance, and efficiency of the treatment is reduced.